A clinically meaningful reduction in perceived stiffness occurred in 29% of patients taking the cannabis extract, which was nearly double the 16% rate with placebo (P=0.004), John Peter Zajicek, PhD, of the University of Plymouth, England, and colleagues found in the MUSEC trial.

Bodily pain, spasms, and other outcomes also favored the cannabinoids, they reported online in the Journal of Neurology, Neurosurgery & Psychiatry.

Nevertheless, a small percentage of multiple sclerosis patients use medical marijuana for relief of symptoms, among which muscle stiffness is highly common, affecting up to 90% of patients at some point in the course of the disease.

"Current symptomatic therapy often provides inadequate relief and may be limited by toxicity," Zajicek's group explained. "As a consequence, people with MS have experimented with many alternative therapies to ease their physical problems, including cannabis."

The National MS Society has cautioned that there's just not enough evidence to recommend marijuana or its derivatives for treating symptoms and that these do carry side effects.

"The fact that marijuana is an illegal drug in many states and by federal statute further complicates the issue," the society's website notes.

The MUSEC trial included 279 British patients with stable MS randomized to double-blind treatment with capsules containing Cannabis sativa extract standardized to contain 0.8 to 1.8 mg of cannabidiol and 2.5 mg of tetrahydrocannabinol (THC) or a matched placebo.

After 12 weeks, the primary outcome of patient-reported feeling of their muscle stiffness being better or very much better compared with the premedication phase was 2.26-fold more likely with the active treatment than with placebo (a category 0 to 3 rating on the 11-point scale).

The results didn't vary by how severe the muscle stiffness was at baseline, whether patients were able to walk, or use of anti-spasticity or analgesic medication, although patients not on anti-spasticity meds saw the biggest benefit of the cannabis extract (38% responders versus 16% with placebo).

Self-reported relief from stiffness also was better at 4 and 8 weeks of treatment.

More patients also reported feeling relief with the cannabis pills than with placebo for muscle spasms (31% versus 13% at week 12, P<0.0025) and sleep quality (34% versus 19%, P<0.005).

Relief from bodily pain was more common with the active treatment over the first 8 weeks but the advantage over placebo didn't reach statistical significance at week 12 (28% versus 19%).

The improvement in pain ratings, though, was significant at the end of the study, with a reduction of 1.2 versus 0.3 points with placebo on the 11-point scale compared with baseline (P<0.025).

Overall MS symptom ratings and the effect of spasticity on body movement also showed significantly greater improvements in the active treatment group.

The researchers noted that they didn't use the Ashworth scale as in prior trials.

"The limitations of the single item, semi-objective Ashworth Scale in measuring the highly complex phenomenon of spasticity are well known, and it is now not recommended for spasticity assessment," they explained.

"As well as difficulties with outcome measures, other problems encountered in evaluating the potential benefit of cannabinoids for MS symptoms have included high placebo response rates and potential unmasking of treatment group, either due to side effects or improved symptoms."

Side effects in the trial were more common overall with the marijuana extract and many of those that occurred more often with it were associated with the "high" feeling from the drug -- dizziness, disturbance in attention, balance problems, somnolence, dry mouth, nausea, diarrhea, fatigue, asthenia, feeling abnormal, urinary tract infection, disorientation, confusion, and falls.

However, the biggest difference in adverse event rates occurred during the titration phase of the study "and can reasonably be attributed to the fast dose escalation," the investigators suggested.

The study was funded by the Society for Clinical Research in Berlin and Weleda.

Zajicek reported receiving consultancy fees from IKF and Bayer-Schering as well as funding from the MRC and NIHR EME to conduct studies using cannabinoids. He is a named inventor in two patents regarding cannabinoid use in multiple sclerosis.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

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